When I was executing "dmsetup resume <device-name>" command,I got the
error shown below. Which basically tells that, "bd_mount_mutex" in
thaw_bdev() is not locked by "dmsetup resume" command and hence it is
not allowing it to unlock also.

On debugging I found out that,"dmsetup suspend <device name>" calls
"freeze_bdev()",which locks "bd_mount_mutex" to make sure that no new
mounts happen on bdev until thaw_bdev() is called.

This "thaw_bdev()" is getting called when we resume the device through
"dmsetup resume <device-name>".
Hence we have 2 processes,one of which locks "bd_mount_mutex"(dmsetup
suspend) and Another(dmsetup resume) unlocks it.

Since this is not allowed in mutex,I reverted back to
bd_mount_sem(semaphore),It worked for me.

So need your comments for changing "bd_mount_mutex" to "bd_mount_sem".